m. nassiri mahallati

The first step to achieving ecological sustainability and intensification in agricultural systems is to have a comprehensive agroecological analysis of agricultural systems. This research analyzed the agroecological ecosystem of potato cultivation in the Torbat-e Heydariyeh Region of Iran over fifteen years (2001-2016). Based on the results, potato yield increased by 0.28 t ha-1 yr-1. The average potential yield of potato was calculated by the FAO method to be 64 t.ha-1. Also, the potential yield did not increase significantly during the study period. The average yield gap of potato was calculated to be 32.44 t ha-1. Also, with increasing yield, the yield gap showed a decreasing trend. The ecosystems experienced a steady rise in intensification, and the stability decreased. It was observed that although nitrogen fertilizer application was increased, its efficiency dropped from 110 kg tuber per kg of nitrogen fertilizer to 70 kg. Due to the decreasing trend of NUpE (Nitrogen uptake efficiency) and NUE (Nitrogen use efficiency) during the studied years, the NUE gap was the main factor in increasing nitrogen consumption, increasing intensification, and reducing stability in the studied systems. Therefore, changing the management method to increase the efficiency of nitrogen consumption can be suggested as the first step for moving towards ecological intensification and improving the sustainability of potato production systems.

 Water is the most frequently used carrier for herbicide applications. Thus, the physicochemical properties of water in spray mixture can affect the activity of herbicides. A high concentration of Na+, K+, Ca2+, Mg2+, Fe3+ and other cations in hard water can decrease herbicide efficacy. Weak acid herbicides that have been antagonized by one or more of the above cations include sethoxydim, 2,4-D, 2,4-DB, clethodim, imazethapyr, tralkoxydim, and glufosinate and glyphosate. Approaches to minimize hard water antagonism have included decreasing the spray carrier volume and using water-conditioning additives that have proven effective at ameliorating cation-caused antagonism include ammonium sulfate, ammonium nitrate, potassium phosphate, and citric acid. Passing hard water containing Ca2+, Mg2+ or Na+ through an external magnetic device results in the nucleation and crystallization of the respective carbonates. As a result, hard water can be softened for a period. Considering that the hardness of Iranian agriculture is increasing and adding an adjuvant to spray solution is also considered to be more environmental contamination, therefore, the physical conversion of hard water to soft water via its passage through a magnetic field is definitely a good alternative. The objectives of this research were to investigate the effect of adding CaCO3, MgCO3, Na2CO3, K2CO3, or Fe2(CO3)3 to distilled water on glyphosate efficacy to jimsonweed (Datura stramonium L.), and to compare the chemical hard water softening methods (ammonium sulfate, ammonium nitrate, citric acid and potassium phosphate) to a new physical hard water softening method (passing carrier through a magnetic field) to Reduce the incompatibility of hard water cations with glyphosate.

 The seeds of jimsonweed were collected from plants in the fields of Qazvin city, Iran. They were stored in the dark at room temperature until use. Bioassays were conducted in a greenhouse located on the Ferdowsi University of Mashhad, Iran. To increase seed germination before starting the experiment, the seeds were washed every 1 hour for 7 days to remove seed germination inhibitors. Twenty-five seeds were sown at 0.5 cm depth in 2 L plastic pots filled with a mixture of sand, clay loam soil, and peat (1:1:1 by volume). At cotyledon-leaf stage, the seedlings were thinned to four per pot. The pots were irrigated every four days with tap water. Treatments were sprayed at the four-leaf stage. The experiment was arranged as a completely randomized design with four replications as a factorial design with factors of carrier type (distilled water alone or containing 0.5 g L-1 of CaCO3, MgCO3, Na2CO3, K2CO3, or Fe2(CO3)3) and hard water softening method (ammonium sulfate, ammonium nitrate, potassium phosphate, citric acid, and passing through a magnetic field) and glyphosate dose (0, 12.81, 25.62, 51.25, 102.5 and 205 g a.i. ha-1). For magnetizing the carriers, it was passed 10 times through a magnetic treatment device modified from Rashed-Mohassel (30). The mixing order for treatment solutions was (i) adding CaCO3, MgCO3, Na2CO3, K2CO3, or Fe2(CO3)3 to distilled water, then (ii) adding/using water conditioning method, and after 15 min (iii) adding glyphosate. Then, the solutions were sprayed after about 5 min using a calibrated moving boom sprayer at 180 L ha-1 at 200 kPa with 11002 flat-fan nozzle. Shoots were harvested four weeks after treatment, dried for 48 h at 70°C, and dry weight was determined. The data of shoot dry weight were subjected to a non-linear regression analysis for determination of ED50 values (herbicide dose needed to obtain 50% reduction in dry weight) using the following logarithmic logistic dose-response model. The relative potency (R), the horizontal displacement between the two curves, was also calculated.

 As judged by the relative potency values given in Table 1, the hard water softening methods decreased the ED50 values when distilled water was used as the carrier. Therefore, the activity of glyphosate against jimsonweed was significantly increased in the presence of the hard water softening methods. There were significant differences in performance among hard water softening methods as ammonium sulfate was the most effective method. Glyphosate activity was not decreased when applied in a K2CO3 solution but it was decreased when applied in Na2CO3, MgCO3, CaCO3 or Fe2(CO3)3 solutions. Except potassium phosphate which had only a significant effect at reducing the antagonism in the CaCO3 carrier; all hard water softening methods could restore glyphosate activity in hard water contaminated carriers to efficacy levels comparable to glyphosate alone in distilled water. There was no statistical difference in response between the magnetized carrier and ammonium sulfate when they were used in Na2CO3, MgCO3, or Fe2(CO3)3 solutions. It is reported that hard water softening methods may adjust the spray solution pH so that more active ingredient can transport across the leaf surface into the plant via ion trapping phenomenon. Ammonium sulfate was the most successful method to ameliorate the decreased glyphosate activity due to antagonism with Na+, Mg2+, Ca2+, or Fe3+ in the spray solution. By adding ammonium sulfate, the sulfate ion () conjugates with the hard water cations and removes free cations from solution by forming cation-SO4 molecule, allowing ammonium ion () to form glyphosate-NH4 molecule. A glyphosate-NH4 molecule diffuses across the cuticle easier and quicker. A mechanism for physical hard water softening method is illustrated in Fig. 2.

 Although the physical hard water softening method was not effective as compared to some chemical hard water softening methods (ammonium sulfate and citric acid), from the point of view of economical and agricultural, applying the physical hard water softening method will be benefit because it needs no chemical.

Predicting yield is increasingly important to optimize irrigation under limited available water to enhance sustainable production. Calibrated crop simulation models therefore increasingly are being used an alternative means for rapid assessment of water-limited crop yield over a wide range of environmental and management conditions. AquaCrop is a multi-crop model that simulates the water-limited yield of herbaceous crop types under different biophysical and management conditions. It requires a relatively small number of explicit and mostly-intuitive parameters to be defined compared to other crop models, and has been validated and applied successfully for multiple crop types across a wide range of environmental and agronomic setting. This study was conducted as a two-year field experiment with the aim of the simulation of water productivity, above ground biomass and fresh and dry yield of tomato using AquaCrop model under different irrigation regimes applied at two growth stages in Mashhad climate conditions. A two-year field experiment was conducted during 2016-2017 growing seasons in the experimental field of Ferdowsi University of Mashhad located in Khorasan Razavi province, North East of Iran. The water-driven AquaCrop model developed by FAO was calibrated and validated to simulate water productivity, above-ground biomass and yield of tomato crop under varying irrigation regimes. AquaCrop was calibrated and validated for tomato under full (100% of water requirements) and deficit (75 and 50% of water requirements) irrigation regimes at vegetative (100V, 75V, and 50V) and reproductive stages (100R, 75R, and 50R). Model performance was evaluated in terms of the normalized root mean squared error (NRSME), the Nash–Sutcliffe model efficiency coefficient (EF), Willmott’s index of agreement (d) and coefficient of determination (R2). The drip irrigation method was used for irrigation. The tomato water requirement was calculated using CROPWAT 8.0 software. The irrigation water was supplied based on total gross irrigation and obtained irrigation schedule of CROPWAT. The 2016 and 2017 measured data sets were used for calibration and validation of AquaCrop model, respectively. Calibration results showed good agreement between simulated and observed data for water productivity in all treatments with high R2 value (0.93), good ME (0.23), low estimation errors (RMSE=0.09 kgm3) and high d value (0.85). The goodness of fit results showed that measured WP values were closer to simulated WP values for the validation season (2017) than for the calibration season (2016). During calibration, (2016), the model simulated the biomass with good accuracy. The simulated above ground biomass values were close to the observed values during calibration (2016) for all treatments with R2 ranging from 0.92 to 0.99, NRMSE in range of 7.4 to 23%, d varying from 0.94 to 1, and ME ranging from 0.71 to 0.98. Validation results indicated good performance of model in simulating above ground biomass for most of the treatments (0.92 < R2 < 0.98, 6.5% < NRMSE < 21.3%, 0.76 < ME < 0.99). During validation (2017 growing season), overall, the trend of biomass growth (or accumulation) was captured well by model. However, the range of biomass of simulation errors was high, especially in treatments with higher stress. Accurate simulation of the response of yield to water is important for agricultural production, especially in an arid region where agriculture depends closely heavily on irrigation. During validation, the model predicted dry and fresh yield satisfactorily (NRMSE = 15.64% and 11.80% for dry and fresh yield, respectively). In general, the AquaCrop model was able to simulate the observed water productivity, above ground biomass and yield of tomato satisfactorily in both calibration and validation stage. However, the model performance was more accurate in non- and/or moderate stress conditions than in sever water-stress environments. In conclusion, the AquaCrop model could be calibrated to simulate growth and yield of tomato under temperate condition, reasonably well, and become a very useful tool to support decision on when and how much irrigate. This study provides the first estimate of the soil and plant parameter values of AquaCrop for simulation of tomato growth in Iran. Model parameterization is site specific, and thus the applicability of key calibrated parameters must be tested under different climate, soil, variety, irrigation methods, and field management.

One of the important factors in the adaptation of plants to new environmental conditions is the appropriate response of development stages to temperature and photoperiod regimes. The thermal time, growing degree days (GDD) or heat unit concept is commonly the basis for modeling phenological development in crop models for different common crops and under-utilized crops. The GDD concept describes crop development as a function of temperature accumulation above the base temperature (lower limit) and in some cases below a cut off temperature (upper limit). Evaluation of plant photoperiod sensitivity is often beneficial help to use appropriate cultivars which in turn to ensure cultivation success. Considering that adaptation of quinoa to new regions demands acclimation to appropriate temperature range also day-length, this study aimed to investigation of quinoa response to Yazd weather condition as an arid region to assess the possibility of quinoa cultivation under these conditions.

This research was conducted through 10 separate experiments and were based on a randomized complete block design with three replications. The experimental treatment consisted of five lines (1, 2, 3, 4 and 5), and one cultivar (Titikaka) which belong to different maturing groups including early, middle and late maturing. Ten planting dates selected to be serial as following: March 29, April 29, May 28, June 28, July 26, August 23, September 6, September 20, January 29, and February 29. Every three days, phenological stages of each line including planting distance to each stage of development including emergence, four leaves, flower bud, panicle formation, pollination, seed filling, seed hardening and ripening were recorded accordingly. Using local weather data and equation 1 the needed GDD for every development stage was calculated:GDD= (Tmax-Tmin)/2-T(1)MS-Excel Ver. 15 was employed to arrange recorded data and required calculating. Fitting equations and plotting the graphs were done using Slide Write Ver. 2 and Minitab Ver. 20 software.  

The results showed that the mean of flowering temperature up to seed formation stage was between 25 and 30 °C for five lines and was between 20 and 25 °C in cultivar 6. The mean length of photoperiod for flowering and seed formation stage of these lines was between 12 and 12.5 hours. The relationship between temperature and day length was inversely related to the number of days of flowering stage, i.e., with decreasing day length and increasing temperature, the number of days for flowering stage was increased. The time required for flowering stage, between 20 to 30° C, for the early maturing cultivar was about 35 days, for the middle maturing lines including 1, 2, 3 and 6 was about 40 days and for the late maturing line 4 was about 45 days. At temperatures higher than 30 °C, a decreasing trend was observed in the number of days required for flowering stage. From the budding stage to the end of the growth period, a significant difference in the GDD was observed for the quinoa lines. The GDD of quinoa was the highest (2530 °C) for late maturing line (4) and was the lowest (1805 °C) for the early maturing cultivar. The effect of planting date on the GDD of quinoa lines showed that moving from March planting date to July, there was an increasing trend on the GDD of quinoa lines and by moving from July planting date to October, a decreasing trend was observed.

In general, quinoa is a short-day plant which is affected by the day length from flowering to seed maturity stages. Line 6 responded qualitatively to day length; however, the other lines responses were quantitatively. The study of the simultaneous effect of temperature and day length showed that temperature has a compensatory effect for day length during flowering stage. According to the results, it seems that the most suitable planting date for early lines suggests in September, for middle maturing lines suggests in August and for late maturing lines suggests in August. The results also showed that line 6 is more suitable than other lines for cultivation in cold regions.

The modeling approach for the simulation of the growth and development of tomatoes in Iran has been overlooked. Calibrated crop simulation models, therefore, are increasingly being used as an alternative means for the rapid assessment of water-limited crop yield over a wide range of environmental and management conditions. AquaCrop is a multi-crop model that simulates the water-limited yield of herbaceous crop types under different biophysical and management conditions. It requires a relatively small number of explicit and mostly intuitive parameters to be defined compared to other crop models and has been validated and applied successfully for multiple crop types across a wide range of environmental and agronomic settings. This study was conducted as a two-year field experiment with the aim of the simulation of soil water content, evapotranspiration, and green canopy cover of tomato using AquaCrop model under different irrigation regimes at two growth stages in Mashhad climate conditions.

A field experiment was conducted over two consecutive seasons (2016-2017) in the experimental field of Ferdowsi University of Mashhad, located in Khorasan Razavi province, North East of Iran. The experiment was laid out in a split-plot design with different irrigation regimes at the vegetative and at the reproductive stage as the main and subplot factors, replicated thrice. In total, 27 plots of 4.5×3 m (13.5 m2) were used at a planting density of 2.7 plants per m2. Seedlings were planted in a zigzag pattern into twin rows, with a distance of 1.5 m between them, so there were four twin rows of three meters in each plot. The distance between tomato plants within each twin-row was 0.5 meters. A buffer zone spacing of 3 and 1.5 m was provided between the main plots and subplots, respectively. The following experimental factors were studied: three irrigation regimes (100= 100% of water requirement, 75= 75% of water requirement, 50= 50% of water requirement) and two crop growth stages (V= vegetative stage and R= Reproductive stage). The drip irrigation method was used for irrigation. The tomato water requirement was calculated using CROPWAT 8.0 software. The irrigation water was supplied based on total gross irrigation and obtained irrigation schedule of CROPWAT. Model accuracy was evaluated using statistical measures, e.g., R2, normalized root means square error (NRMSE), model efficiency (E.F.), and d-Willmott. The 2016 and 2017 measured soil and canopy data sets were used for calibration and validation of the AquaCrop model, respectively.

For a water-driven model, such as AquaCrop, it is important to evaluate its effectiveness in simulating soil water content. During calibration (2016), the model simulated the soil water content with good accuracy. The simulated soil water content values were close to the observed values during calibration (2016) for all treatments with R2 ranging from 0.90 to 0.97, NRMSE in range of 8.47 to 17.96%, d varying from 0.76 to 0.99, and M.E. ranging from 0.87 to 0.96. Validation results indicated the good performance of the model in simulating soil water content for most of the treatments (0.79<R2<0.99, 10.04%<NRMSE<18.65%, 0.77<ME<0.92). Appropriate parameterization of canopy cover curve is critical for the model to provide accurate estimates of soil evaporation, crop transpiration, biomass, and yield. In general, the calibration results showed good agreement between simulated and observed data for canopy cover development in all treatments with high R2 values (>0.87), good E.F. (>0.61), low estimation errors (RMSE, ranging from only 4.5 to 9.2) and high d values (>0.92).

The AquaCrop model (version 6.1) was calibrated and validated for modeling soil water content, evapotranspiration, and green canopy cover for tomatoes under drought stress conditions. In general, soil water content, evapotranspiration, and green canopy cover of tomato were simulated by AquaCrop model with acceptable accuracy in both calibration and validation stages. However, the model performance was more accurate in no and/or moderate stress conditions than in severe water stress environments. In conclusion, the AquaCrop model could be calibrated to simulate the growth and soil water content of tomatoes under temperate conditions reasonably well and become a very useful tool to support the decision on when and how much irrigate. For R2, values > 0.90 were considered very well, while values between 0.70 and 0.90 were considered good. Values between 0.50 and 0.70 were considered moderately well, while values less than 0.50 were considered poor. Root mean square error ranges from 0 to positive infinity and expresses in the units of the studied variable. An RMSE approaching 0 indicates good model performance.

Recently self-sustaining, diversified, low-input, and energy-efficient agricultural systems like intercropping have been considered as the efficient way to achieve the sustainability in agriculture. Intercropping as an old agricultural practice, have been followed especially at the small scale and subsistence farming. It can be defined as the agricultural practice of growing two or more crops or ecotypes together in the same field. Intercropping brings diversity of species in the cropping systems, and is considered to make the systems more resilient against environmental perturbations, thus enhancing food security. It provides high insurance against crop failure, especially in the extreme weather conditions like temperature stress, drought, flood, frost, pest infestation etc. In fact, intercropping is claimed to be one of the most significant cropping techniques in sustainable agriculture, and many researches and reviews attribute its utilization to the number of environmental benefits from promoting land biodiversity to diversifying agricultural outcome. Legumes after cereals are the second source of human food and in Iran they are the second most important food. Due to the importance of legume intercropping in the sustainability of agricultural systems, the objective of the present work was to evaluate the effect of row intercropping of three bean ecotypes red bean, pinto bean and cowpea bean as replacement series on the physiological growth indices under climatic conditions of Mashhad.

This experiment was conducted based on a randomized complete block design with nine treatments and three replications at the Agricultural Research Station, Faculty of Agriculture Ferdowsi University of Mashhad during 2016-2017 growing season. Treatments were 75% red bean+ 25% pinto bean, 75% red bean+ 25% cowpea bean, 25% red bean+ 75% pinto bean, 25% red bean+ 75% cowpea bean, 75% pinto bean+ 25% cowpea bean, 75% cowpea bean+ 25% pinto bean and their monoculture. In order to measure the growth indices, the destructive samplings were carried out every 14 days from 0.15 m2 of row in each plot. All bean ecotypes were harvested by cutting at the soil surface. The studied indices were leaf area index (LAI), dry matter accumulation (DM), crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR).

The highest leaf area index for red bean, pinto bean and cowpea ecotypes were observed in their monoculture with 2.45, 1.45 and 3.60, respectively. The fast period of vegetative growth and dry matter accumulation were observed at 65-80 days after planting with a small decline afterwards until physiological maturity. The maximum dry matter accumulation for these ecotypes was obtained in their monoculture. Crop growth rate reached its peak 65 days after emergence followed by a decreasing trend afterwards. The highest crop growth rate was observed in pinto bean with 27 g m-2 day-1. At the beginning of growth stage, due to more penetration of light into the canopy and less shadow of the leaves the less respiration, RGR was more and its reduction slope was less. As time passes and vegetative and reproductive organs grow more, the shadow of leaves on each other increases and therefore after words RGR decreased. Also, net assimilation rate reached to its peak 60 days after emerging and decreased.

The results of showed that intercropping of bean ecotypes with increasing plant density, increased the leaf area index (LAI) and dry matter accumulation (DM) of both crops in monoculture and mixed culture which could be due to increased vegetation and it's closer to optimum density in mixed culture and better use of environmental resources. However due to different criteria of these ecotypes associated with better use of water, radiation and nutrient resources when they are intercropped, physiological growth indices were increased. Overall following this agroecological practice in cropping systems could keep contribution to move the current agroecosystems one step towards sustainability.

Intercropping is an old agricultural practice which is growing of multiple crop species at the same time in the same place. Traditionally, intercropping has been used to increase crop production and the efficiency of the resource as well mitigate any possible risk. Intercropping has been shown to decrease the risk of crop failure by increasing the crop yield stability over time. Intercropping creates biodiversity in the cropping systems, and it is considered to make the systems more resilient against environmental perturbations, thus enhancing food security. Land equivalent ratio (LER) is often conceded as an indicator to determine the efficacy of intercropping that measure the land productivity. LER may be interpreted as the relative area required by sole crops to produce the same yields as achieved in a unit area of intercrop. The objective of the present work was to evaluatethe effect of row intercropping of three plant species such as sunflower, pumpkin and common bean on the yield, yield components and land equivalent ratio under climatic conditions of Mashhad.  

This experiment was conducted based on a randomized complete block design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad, Iran during two growing seasons of 2015-2016 and 2016-2016. The treatments were double (H:C, H:P, C:P) and triple (H:C:P and HH:CC:PP including one row and two rows of each species) arrangements of sunflower, pumpkin and common bean as replacement series and their sole cropping. Investigated traits were plant height, 100-seed weight, number of seeds per head, head diameter, seed weight per plant, biological yield, seed yield and harvest index of sunflower, seed weight per fruit, 100-seed weight, fresh weight of fruit, dry weight of fruit, number of seeds per fruit, dry weight of plant, biological yield, seed yield and harvest index of pumpkin and plant height, number of pods per plant, number of seeds per pods, number of branches per plant, dry weight of plant, pod weight per plant, seed weight per plant and 100-seed weight, biological yield, seed yield and harvest index of common bean. The LER was calculated as the sum of relative yields of component crops in an intercrop versus sole crops. For analysis of variance SAS ver 9.2 was used. All the means were compared according to Duncan multiple range test (p≤0.05).

The results showed that the effect of different intercropping arrangements of sunflower, pumpkin and common bean was significant (p≤0.05) on their yield components, seed yield, biological yield and harvest index. The highest seed yield of sunflower, common bean and pumpkin were observed in triple cropping as two rows (10158 kg.ha-1), sole cropping(10493 kg.ha-1) and common bean+ pumpkin (25014 kg.ha-1), respectively. The maximum biological yield of sunflower, pumpkin and common bean were observed in it sole cropping, triple cropping as one row and sole cropping. The highest and the lowest land equivalent ratio were calculated with triple cropping as one row (1.69) and sunflower+ common bean (1.06), respectively.

Results revealed that growth, yield components and yield of sunflower, pumpkin and common bean were significantly affected by intercropping arrangements. However due to different criteria of these species associated with better use of water, radiation and nutrient resources when they are intercropped, land use efficiency was increased. Acknowledgement This research (40982) was funded by the Vice Chancellor for Research of Ferdowsi University of Mashhad, which is hereby acknowledged.

In the foreseeable future, plants are still the most important source of human food supply, and given the rapid rise in demand for food in developing countries, the demand for food will increase sharply over the next 20 years. Compression is the most important factor in increasing agricultural production. One of the useful indicators in determining the compression rate is the use of agronomic index. In Nepal, an applied definition has been used to compress agriculture, which includes increasing the number of crops per unit area in a crop season, along with the trend of chemical changes to improve plant performance. One of the important indicators used by many researchers is made by Boserup (1966). In this definition, agricultural compression  means increasing the cultivation of crops in a given period in an agricultural system., The idea of increasing the frequency of planting important crops originated in agriculture prior to industrialization and was the only way to increase crop production in one year. This concept later became more comprehensive by other researchers by adding the differences in the length of sowing and planting of crops. In a number of studies, the frequency of products indicating the amount of land use has been used as a compression index.

In order to study the trend of changes in crop density, agronomy and stability in agricultural production, statistical data of 15 agricultural variables including crop area and rainfall in different provinces of the country for the period of 50 years from 1961 to 2011 have been obtained from the Statistical Yearbook, databases The Ministry of Agriculture, the Center for Statistics of Iran and the FAO Database.
Agronomic index was used to study the land use status of arable land and an aspect of compression including land cover with one-year cultivars.

Based on the average, total agricultural density in 1971, 2004 and 2011were 9.26, 8.48 and 8.80, respectively, and the mean of three years was 8.94 months. The lowest index of agricultural density index in 1350 belonged to southern coastal provinces (Hormozgan and Bushehr) and Mazandaran with average of 6.98 and 7.33 months, respectively. In 2004 Guilan and Mazandaran provinces had the least index of 4 and 62.5 months, and in 2011 the lowest rate of this indicator was in Gilan and southern coastal provinces, with a period of coverage of 63.6 and 5.3 months, respectively. Considering that in most regions of the country more than half of the cultivated area is allocated to wheat, and also wheat remains on the ground  longer than the other crops, therefore, wheat cultivation owns the most important share  in the determination of the index of agronomic agglomeration (or crop cover). On the other hand, in the northwestern regions due to climatic conditions and colder periods of time, cereals especially wheat remail on the ground longer ,so the main reason for the higher index of agronomy in these areas is that wheat is present at the surface of earth. The study of agronomy in the country's arable crops showed that, contrary to expectation, in areas with higher rainfall the duration of land cover is less and soil remains without cultivation a long time in the year, due to the cultivation of crops such as rice. Therefore, changing the pattern of planting is essential in these areas .

The results of this study showed that due to the dominance of cereal cultivation in cropping pattern, crop density was affected by the cropping area of ​​these plants. Food security is one of the basic needs and increasing the production per unit area isone of the important ways to achieve it.  So, changing the pattern or planting system is necessary in areas where compression is low.

Medicinal plants are looked upon not only as a source of affordable health care products but also as a source of income. There is a growing demand for plant-based medicines, health products, essential oils, fragrances, cosmetics and natural aroma chemicals in the markets. Cultivation of medicinal and aromatic plants has several advantages such as higher net returns per unit area, low incidence of pests and diseases, improvement of degraded and marginal soils, longer shelf life of end products and foreign exchange earning potential. Intercropping is a multiple cropping system that has been practiced for many years in various methods in most of the regions. It has played important roles in the redistribution of soil nutritional resources and establishment of soil microbial diversity. Legumes have been intercropped with medicinal plants for many years. Land equivalent ratio (LER) is often used as an indicator to determine the efficiency of intercropping. It is the most common index adopted in intercropping to measure the land productivity. The objectives of this study were to determine the effects of black seed (Nigella sativa L.) intercropped with fenugreek (Trigonella foenum-graecum L.) in additive series on their yield and yield components and LER.
 

An experiment was performed based on a randomized complete block design with six treatments and three replications at the Agricultural Research Station, Ferdowsi University of Mashhad during growing season of 2015-2016. Intercropping ratios were 25% B (black seed) +100% fenugreek (F), 50% B+100% F, 75% B +100% F, 100% B+100% F and their monoculture. Studied traits were the number of branches per plant, the number of follicles per plant, the number of seeds per follicle, 1000- seed weight, seed yield, biological yield and harvest index for black seed and the number of branches per plant, the number of pods per plant, the number of seeds per pod, 1000- seed weight, seed yield, biological yield and harvest index for fenugreek. LER was calculated as the criterion for intercropping.
The treatments were run as an analysis of variance (ANOVA) by using Minitab to determine if significant differences existed among treatments means. Multiple comparison tests were conducted for significant effects using the LSD test.
 

The results showed that the different intercropping ratios of black seed with fenugreek had significant effect on the number of branches per plant, the number of follicles and pods per plant, the number of seeds per follicle/pod, seed yield and biological yield. The highest and the lowest seed yield of black seed were observed for monoculture and 25% black seed+100% fenugreek with 291 and 107 kg.ha-1, respectively. The maximum and the minimum seed yield of fenugreek were related to its monoculture and 100% black seed+100% fenugreek with 655 and 363 kg.ha-1, respectively. When the two plants are grown together, yield advantages occur due to their differences to use resources.
LER of the black seed/ fenugreek intercropping system ranged from 1.12 to 1.24, and thus land use efficiency was significantly enhanced by this intercropping system. LER was much higher than one in all of the intercropping ratios, indicating the intercropping yield advantage. The maximum LER was calculated for 75% black seed+100% fenugreek with 1.24.
 

Fenugreek intercropped with black seed showed a significant increase in yield, yield components and LER. It has been proved that the effects of intercropping by its involvement in improved soil chemical characteristics, increased nitrogen content (nitrogen biological fixation) has greatly contributed to agroecological services. It can be concluded that intercropping of fenugreek with contributed to productivity increases per unit area of black seed.
Acknowledgement
This research was funded by Vice Chancellor for Research of Ferdowsi University of Mashhad, which is hereby acknowledged.

The concept of ecological footprint was first proposed by Rees (1992) and further developed by Wackernagel and Yount (2000). This is an index based on the land area needed for basic requirements and also the waste disposal of an individual in a specific geographic location and usually calculated on the basis of area per capita which is normally global hectare (Gha) per capita. Based on the report of World Wildlife Found, total world ecological footprint for the year 2010 has been estimated to be 18.2 billion global hectares (Gha) with a per capita 2.7 Gha. This index is reciprocal of carrying capacity.
During the last two decades ecological footprint accounting is used widely for evaluation of ecosystems sustainability. However, limited information is available about ecological footprint of Iran and its components. In this research the state of production and consumption of different food stuffs and ecological footprint of food were calculated for Iran and the results are compared with other countries.

Data was collected for different group of agriculture foods including cereals, oil crops, pulses, dairy products, meat, fruits and vegetables from Ministry of Jihad Agriculture, Ministry of Commerce and also from other published data in official databases in the country. Calculation was made by the method provided in the literature.
Based on these factors ecological foodprint for each food product (efi) on the bases of Gha can be calculated from equation 1.
Equation (1)
In which efi: is the foodprint for product i, Ai: is the land area required for the same product i and fe,i: is the conversion factor for product i (Gha per ha).
Calculation of foodprint
Equation (2)
Equation (3)
Where EF is total ecological footprint (Gha), ef: per capita ecological footprint in terms of Gha and N: total population of the country.

The amount of total food production and consumption in 2013 were estimated as 89.5 and 94.6 Mg, respectively with self-sufficiency coefficient (production: consumption ratio) of 0.87. Self-sufficiency of cereals, oil crops and sugar crops were calculated as 0.69, 0.12 and 0.48, respectively that shows these food groups are highly import-dependent. However, production of vegetables and fruits exceeded their consumption and for other food items consumption was balanced by production. Ecological footprint of food estimated as 0.88 Gha/person and increased to 1.04 ha/person when calculated based on local hectares. Component analysis showed that this difference was due to lower efficiency of cereal and meat and dairy production systems of the country compared to world averages. Meat and dairy products accounted for 48% of food footprint of Iran and 33% of this footprint was due to cereals. Based on our results, Iranian food footprint is higher than Asia (0.7 Gh/person) and is almost the same as the world average (0.9 Gh/peron). Moreover, footprint of food is increased over the country by 76% during years 2000-2013 and this trend could led to severe environmental consequences.

Except for vegetable oils, sugar and cereals, the production and consumption of other groups of food materials are in balance, even for some groups such as fruits and vegetables. There is a small surplus in production over consumption for some extent dairy products. Foodprint for Iran is higher than the value for Asia and is similar to average for the world. In general, foodprint differs significantly amongst the nation and as expected this value is higher in those countries with higher consumption of meat. Higher demand for consumption of meat has caused an increase in indirect consumption of cereals for meat production. It should be noted that since foodprint is based on global hectare, comparison between countries and regions are simply possible. In fact if yield of a crop at national level is increased but world mean yield does not change, foodprint based on global hectare remains unchanged but if it is calculated on the bases of local hectare, foodprint will decrease. Therefore, system efficiency can be evaluated at national level, by comparison of foodprint at two different scales of global hectare and local hectare.

This research (14920.1) was funded by vice chancellor for research of Ferdowsi University of Mashhad, which is hereby acknowledged.

To realize global food demand by 2050 world cereal production should be increased up to 49% compared to 2006. This level of production could be achieved by annual yield increment of 1.16%. However, the current rates are much lower. At the same time, there is a very restricted area to increase cultivated lands because of resource limitation, provided that increase in crop yields is the main option to sustain food security. Potential yield (YP) could be achieved when limiting and reducing factors are completely absent during crop growth. YP is an indicator for the yielding capacity of a given environment and management system and estimating the difference between YP and actual yield, known as yield gap, is crucial for improvement of crop production systems at regional or national scale. In this study yield gap and its temporal trend for sugar beet, irrigated and rainfed wheat are estimated over Khorasan Razavi province based on the method developed by Global Yield Gap Atlas. Following the protocol provided by Global Yield Gap Atlas, Khorasan province was clustered into agroclimatic zones using the proposed indices (cumulative degree days above 0 ºC, aridity index and temperature seasonality) based on 10 years (1384-1393) weather data. YP of sugar beet and irrigated wheat for the study period in the climatic regions was first estimated for selected cities within each region using LINTUL model and finally the simulation results were up scaled from cities to region and from regions to the whole province. The model was cross-validated against measured data using leave-one-out (LOO) method to increase accuracy of predictions. Potential yield of rainfed wheat (YW) was estimated from frontier production function which was fitted to yield data over a wide range of annual precipitation. Yield gap (YG) of the studied crops was estimated as the difference between potential (YP) and actual yields (YA) for each region and over the 10-year period. In addition exploitable gap (YG85%=85%YP-YA) was also calculated. The accuracy of LINTUL model for simulation of sugar beet and irrigated wheat yields was considerably increased after cross validation and the prediction error was reduced by 6.5 - 7.8%. Mean YP of irrigated wheat in the climatic region 1 (temperate, semi-dry), 2 (hot, dry) and 3 (temperate, dry) was respectively, 7248, 6478 and 7852 and for the whole province 6936 kg ha-1. Time trend of YP for irrigated wheat was not significant in 3 climatic regions however, high annual variation of YP was found over the studied period. Results indicated that up to 74% of this variation was accounted for by changes in the effective grain filling period in response to temperature. YG85% of irrigated wheat in all climatic regions was increased up to 4 t ha-1 during 1384-1388 but decreased later on so that relative gap was 0.48-0.50 of YP in 1993. Average YW of rainfed wheat in the climatic regions of the province was estimated as 2000-2800 kg ha-1 with a negative trend due to decreased precipitation, the highest negative slope in YW (59 kg ha-1 y-1) was found in the hot dry region. Rainfed wheat showed an extremely high yield gap in all climatic regions and mean relative yield gap (YG/YW) was estimated as 0.75-0.80 over the province. Mean YP of sugar beet in different climatic regions of the province was estimated from 78 to 88 t ha-1 with the lowest potential in hot-dry region. However, declining trend was found in the yield gap of sugar beet in all studied regions with the highest gap filling rate of 1.44 t ha-1 y-1 in temperate-dry region. Simulated YP of sugar beet and irrigated wheat were higher in temperate-semi arid regions of the province and lower in hot-dry regions. However, cold-semi arid regions had the highest YW of rainfed wheat. When up-scaled over the province, YG85% was about 50% of YP for irrigated wheat and sugar beet and 25% for rainfed wheat. It was concluded that closing yield gap of sugar beet and irrigated wheat would be possible mainly by improving management practices however, for rainfed wheat breeding strategies should be considered as the first priority.

Harvesting of medicinal plants from their natural habitats, put them in danger, hence their domestication is needed. In this context, knowledge of the properties of these plants, including the cardinal germination temperatures are necessary. In order to determine the cardinal temperatures and the effect of temperature on the percentage and rate of germination in Plantago major ecotypes (Birjand, Ghaen, Torbathydarieh, Mashhad, Kalat and Bojnord) an experiment was conducted based on factorial in a completely randomized design with 9 temperature levels (5, 10, 15, 20, 25, 30, 35, 40 and 45 °C) and four replications in Crop Physiology Laboratory, Ferdowsi University of Mashhad in 2013. To determine the cardinal temperatures Intersected-Lines Model and Five-Parameters Beta Model were used. Results showed that maximum germination percentage was obtained at 30 °C while maximum germination speed achieved at 35 °C in Bojnourd and Birjand ecotypes, respectively. The highest germination percentage was observed in Birjand ecotype at the temperature range of 20 to 35 °C. Based on models fitted depending on the ecotype, cardinal temperatures  (minimum, optimum and maximum) germination were determined (6.3 to 9.8, 1.8 to 5°C) ,(31.1 to 35.9, 28.6 to 35.2°C) and (43.3 to 45.1, 45 to 45.6 °C) of Intersected-lines and Five-Parameters Beta Model, respectively. Diversity in cardinal temperature of plantago major ecotypes could be due to different environmental conditions where they were evolved and adapted

In order to study individual and integrated effects of biological، organic and chemical fertilizers on milk thistle (Silybum marianum L.) quantitative and qualitative traits، a field experiment was conducted at Research Station، Faculty of Agriculture، Ferdowsi University of Mashhad، Iran during growing season of 2010-2011. A complete randomized block design with twelve treatments and three replications was used. The treatments were: control، vermicompost (V)، poultry manure (H)، chemical fertilizer (CH)، mycorrhiza (M) (Glomus mosseae)، biosulfur (B) (Thiobacillus sp.)، M+V، M+CH، M+H، B+V، B+CH، B+H. The results indicated that the all treatments affected the number of inflorescences per plant، inflorescences diameter and grain yield significantly and other traits weren’t affected by treatments. However، mean comparisons proved promising results for reduction in application of chemical fertilizer and its replacement with biological and organic fertilizers. Application of biosulfur increased the number of seeds per capitula in comparison with control up to 73%. The maximum and the minimum amounts of yield were obtained in M and M+CH، respectively. Other factors affected the yield approximately in the same rate. There was a significant enhancement (26%) in seed oil percentage by using M+H compared to poultry manure. The highest silymarin related to the use of Mycorrhiza and the lowest was obtained in M+CH. The maximum silybin was observed in Mycorrhiza treatment. The application of simple and integrated fertilization systems of organic and biological fertilizers can be effective to achieve a balance in applying chemical fertilizers in order to improve soil fertility، increase soil organic matter and also approach sustainable agriculture in farming milk Thistle.

Optimum uses of water and nitrogen resources are the most important factors in agricultural systems due to limitations of agricultural inputs especially water. In order to investigate the effect of different levels of nitrogen fertilizer and irrigation on efficiency and productivity of water consumption in three crop (sugar beet, corn and sesame) an experiment was carried out as strip split plot based on randomized complete block design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad during growing season of 2008-2009. The main, sub and strip factors were three species (sugar beet, corn and sesame), three irrigation levels (100, 75 and 50% of water requirement of each crop) and four nitrogen levels (0, 50, 100 and 150 kg.ha-1), respectively. The result showed that the highest water use efficiency was observed as 2.4, 1.8 and 1.5 kg DM.m-3 in corn, sugar beet and sesame, respectively. The maximum water use productivity was obtained for sugar beet (4200 Rails.m-3), sesame (2123 Rails.m-3) and then for corn (1768 Rails.m-3). Interaction effect between water and nitrogen was significant on water use efficiency and productivity for all three studied crops. Water use efficiency declined up to 19% by decreasing 25% of water requirement. Water use productivity decreased in all three studied crops by increasing nitrogen consumption. It seems that high nitrogen level could not be affect on reducing drought stress effects.

Climate change by increasing concentrations of greenhouse gases, particularly carbon dioxide, has led to increase attention to the carbon sequestration through the restoration and protection of vegetation cover. In this regards, ecosystems of arid regions have a special importance. In this study the effects of reconstruction and conservation, on soil carbon sequestration of the region of the International Carbon Sequestration Project in Hussein Abad, South Khorasan province of Iran was investigated by a simulation approach using RothC model. In addition, the effects of climate change (increasing temperature and decreasing rainfall) on soil carbon sequestration potential was studied. In the studied area, replanting was done in 2004 and then soil samples were taken every two months during 2010-2011. After collecting the required input data for RothC model (climate, soil and management input data), the model was evaluated and validated for the study area. Moreover, soil carbon sequestration was studied under climate change condition. The simulation results revealed that the RothC model is applicable in rangelands of dry and warm regions, because it estimated the soil carbon changes over the time with proper accuracy. The amounts of model performance index, R2 and RMSE were 0.98, 98% and 0.01, respectively. Simulation study indicated that soil carbon storage will increase from 2011 to 2050 and will be affected by climate change and protection programs. Based on model estimation the amounts of soil carbon in preotected areas will be higher than non-protected areas. Moreover, in non-climate change scenario the amounts of soil carbon will be higher than climate change scenario in 2050.

In order to study the response of wheat (Triticum aestivum) cv. Chamran and wild barley (Hordeum spontaneum) to different herbicides، a pot dose response experiment was conducted in a completely randomized design with three replication at Research Greenhouse of Ferdowsi University of Mashhad in 2008. Different doses of herbicides including Clodinafop propargyl، Pinoxaden، Sulfosulfuron، and Metsulfuron-methyl+ Sulfosulfuron، were applied post-emergence at 2-3 leaf stage of wheat and wild barley and Isoproturon+Diflufenican was applied pre-emergence. Plant dry weight of each treatment was determined three weeks after herbicide application، then GR50، GR25، and herbicide selectivity indices were determined for each herbicide. Results showed that due to wild barley high tolerance، no herbicide could completely control this weed in wheat without injury to wheat. Among all herbicides، Metsulfuron-methyle+Sulfosulfuron was the best one for selective control of wild barley in wheat، which reduced wild barley biomass by 32% in recommended dose. Clodinafop propargyl and Pinoxaden، even at higher doses couldn’t reduce wild barley biomass and can not be used for wild barley control in wheat. Sulfosulfuron had little influence on wild barley at recommended dose، but at higher doses reduced both wild barley and wheat biomass significantly.

One of the most problems in black seed yield reduction is weed interference with this medicinal plant for resources such as macro nutrients. A field experiment was conducted at Agricultural Research Station, Ferdowsi University of Mashhad, Iran, during 2009-2010 growing season. The experiment was laid out in Randomized Complete Block Design (RCBD) with 12 treatments and three replications. Two sets of treatments consisting of weed-infested and weed-free periods were used. In the first set of treatments, weeds compete with black seed until 0, 14, 28, 42, 56 and 70 day after emergence (weed-infested periods). In the second set, plots were kept free of weeds until the mentioned stage (weed-free periods). Results indicated the contents of phosphorus and potassium in weed biomass significantly increased by increasing weed competition durations. However, the percentage and content of phosphorus and potassium in black seed biomass significantly showed a decreasing trend as the weed-black seed competition periods increased. Weed interference with black seed for full growth season decreased contents of phosphorus and potassium in black seed biomass more than 7 and 8 times, respectively. In addition, effects of weed-free and weed-infested periods on decreasing uptake and phosphorus and potassium use efficiency in black seed were significant. Reduction in phosphorus and potassium uptake efficiency of black seed was indicating weak competitiveness of this medicinal plant with its relative weed community.

In order to investigate the effect of fall and winter planting dates on phenological and morphological traits, yield and yield components of four cumin (Cuminum cyminum L.) landraces, an experiment was conducted at the Research Farm of Agricultural College of Ferdowsi University of Mashhad as a split plot based on randomized complete block design with three replications in 2005-06 growing season. Four planting dates (11th Nov., 11th Dec., 20th Feb. and 17th Mar.) were allocated to main plots and four landraces (Ghayen, Torbat-e-heidariyeh, Sabzevar and Khaf) were assigned to sub plots. The results indicated that the effects of planting date, landrace and interaction effect of these two factors on plant height, percent of plant survival after winter, yield components, seed yield, biological yield and harvest index were significant. With respect to plant height, there was no difference between fall (11th Nov. and 11th Dec.) and winter (20th Feb.) planting dates, while plant height in the fourth planting date (17th Mar.) decreased severely. The lowest percent of plant survival was observed in the fall sowing dates, while the third and fourth plantings had no plant mortality, for not exposing to cold conditions. The maximum percent of plant survival belonged to Ghayen and Khaf landraces with 85% and 84% respectively, and Torbat-e-heidariyeh had the lowest percent of plant survival with 59%. The greatest number of umbels per plant, number of seeds per umbel, 1000 seeds weight and seeds weight per plant were achieved in the first planting date. Despite priority of the first planting date in yield components over other planting dates, the greatest seed yield and biological yield observed in the third planting date (20th Feb.). With regard to seed yield and biological yield, Ghayen in the third planting and Torbat-e-heidariyeh in the first planting had the greatest and the lowest yields, respectively. Since the fall and winter planting dates led to improve plant growth particularly vegetative growth, plant height and some of yield components in contrast with spring sowing date, it can be concluded that with planting cold tolerant cumin genotypes due to decreasing the plant mortality in cold conditions, cumin yield will be improved.

In order to study the effects of four chickpea cultivar (Cicer arietinum L.) on vegetative growth of sunflower (Helianthus annus) and corn (Zea mays), two separate experiments was conducted at Research Greenhouse of Ferdowsi University of Mashhad in 2005. Experiments were done in a factorial arrangement of treatments with two factors based on completely randomized design with 4 replications. Factors included chickpea cultivars (Karag12-60-31, Filip 84-482, Gam, ILC 482, and no residue control) and planting date of corn and sunflowers within root residues of chick pea (seeds planted simultaneously, 2 weeks, and 4 weeks after harvesting of chickpea shoots). Seeds of corn and sunflower were planted within root residues of chickpea. Results showed that root residues of chickpea cultivars influenced height and shoot weight of sunflower significantly. The lowest sunflower height was obtained when they were planted within root residues of Flip and ILC cultivars, which decreased 13.7 and 11.1% relative to control, respectively. Planting date of sunflower within root residues of chick pea cultivars had a significant effect on sunflower leaf area, shoot weight, and its root/shoot ratio. So that, lowest leaf area, shoot weight, and also highest root/shoot ratio was obtained in third planting date. Results showed that lowest plant height, leaf area, root weight, shoot weight, and also highest root/shoot ratio of corn (6 weeks after planting) was obtained after planting within chickpea cultivars, Gam and ILC. Also the effect of corn planting date was significant. The lowest root and shoot weight, and root/shoot ratio of corn was obtained in the earliest corn planting date. Therefore, corn plants showed more sensitive than sunflower after planting within chickpea cultivars, and the highest inhibitory effects resulted in the earliest corn planting date.

The effect of split application of nitrogen fertilizer on dry matter (DM) partitioning patterns, yield and quality of sugar beet was studied in a field experiment at Brat Abad, Fariman during 2001 growing season. Three levels of nitrogen fertilizer (N, 70; N2, 140; N3, 210 kg N/ha) were split as S1, %100 at sowing; S2, %75 at sowing and %25 at thinning; S3, %50 at sowing and %50 at thinning; S4, %25 at sowing and %75 at thinning. Factorial experiment based on a randomized complete block design with 4 replications was used. Dry matter partitioning towards storage roots in N1 and in N2 treatments switched at 66 and 76 day after emergence, respectively. In S1 spliting pattern more DM was allocated to root in all growth stages. So that in 1400 GDD (5 Aug) amount of dry matter partitioning to storage roots and tops was equal to %50 while at this stage, partitioning of dry matters to storage roots in S2, S3 and S4 were % 47, % 44 and % 38, respectively. Nitrogen levels had significant effect on polarity, Na, K, recoverable sugar yield, white sugar content and molass sugar. However, these effects on root and sugar yield and N-amino was not significant. Higher rates of nitrogen fertilizer, led to decrease in polarity, white sugar content and recoverable sugar yield. However, root yield, Na, K, N-amino and molas sugar increased in response to N levels. Maximum net sugar yield (4.4 ton/ha) was obtained in the lowest N application. In this study, effect of different patterns of nitrogen spliting and interaction between spliting patterns and nitrogen rates on quality and quantity of sugar beet was not significant. However, maximum net sugar yield (4.8 ton/ha) was obtained in N1S1 where the lowest level of N fertilizer was applied at sowing.

In order to evaluate the effect of different planting ratios on yield and yield components of sesame and chickpea in intercropping, an experiment was conducted in Research Farm of Faculty of Agriculture, Ferdowsi University of Mashhad in 2007. The treatments were arranged in split plots based on randomized complete block design with three replications, consisting of two planting methods namely row planting and mixed planting as main plot and five planting ratios including chickpea monoculture, sesame monoculture, 10% chickpea+100% sesame, 20% chickpea+100% sesame, 30% chickpea+100% sesame as sub plot. The results showed that the highest sesame yield of 1.8 t/ha was obtained in 20% chickpea+100% sesame intercropping at row planting pattern and the lowest yield of 0.74 ton/ha was obtained from 10% chickpea+100% sesame ratio with mixed planting. Land equivalent ratio (RYT) showed that with 20% chickpea+100% sesame, 30% chickpea+100% sesame and 10% chickpea+100% sesame ratio the yield was respectively 39% (RYT=1.39), 28% (RYT=1.28) and 24% (RYT=1.24) more than monoculture. This could be attributed to better utilization of environmental resourses by these combinations of the crops.

In order to evaluate the effect of intercropping with replacement and additive series for hemp (Cannabis sativa L.) and sesame (Sesamum indicum L.), a field experiment was conducted during growing season 2006-07 at the Agricultural Research Station of Ferdowsi University of Mashhad, Iran. A randomized complete block design with three replications was used. Treatments included different combinations of intercropping with replacement (75%sesame+ 25% hemp, 25%sesame+ 75% hemp, 50%sesame+ 50% hemp) and additive (50%sesame+ 100% hemp and 100%sesame+ 50% hemp) series and their monoculture. Results indicated that the highest and the lowest leaf area index (LAI) and dry matter (DM) accumulation of hemp were observed in 50% sesame+ 50% hemp (2.99 and 1921.7 g.m-2) and 50% sesame +100% hemp (1.06 and 929 g.m-2), respectively. The highest and the lowest LAI and DM accumulation of sesame were observed in monoculture (1.34 and 551.27 g.m-2) and 50%sesame+ 100% hemp (0.23 and 51.73 g.m-2), respectively. The maximum crop growth rate (CGR) of hemp and sesame were observed in 50% sesame+ 50% hemp (76.58 gm-2day-1) and monoculture (22.78 gm-2day-1), respectively. It seems that the intercropped sesame with hemp reduced the growth indices of sesame due to increasing shading on it and decreasing the absorption of radiation.

In order to study radiation use efficiency and radiation interception in intercropping of herb sweet basil (Ocimum basilicum L.) and common bean (Phaseolus vulgaris L.), an experiment was conducted at the Agricultural Research Station, Ferdowsi University of Mashhad, Iran during growing season of 2008. Treatments were 1) sole crop of bean, 2) sole crop of sweet basil, 3) strip intercropping of bean and sweet basil (four rows bean and two rows sweet basil), 4) strip intercropping of bean and sweet basil (two rows sweet basil and four rows bean), 5) row intercropping of bean and sweet basil. Sweet basil was harvested at two times during the course of experiment. For this purpose a complete randomized block design with three replications was used. Results showed that in intercrop the fraction of intercepted radiation (F) was higher than the sole crop F. radiation use efficiency (RUE) of sweet basil in intercrop treatments was increased compared to sole crop and highest RUE of sweet basil obtained in secondary harvest of row intercropping (3.4 g.MJ-1), and the highest RUE of bean obtained in row intercrop too (2.4 g.MJ-1). Light extinction coefficient of bean was obtained as 0.55 and sweet basil 0.47, respectively. The highest Leaf area index (LAI) in bean was obtained in sole crop (4.3) and the highest LAI in sweet basil in first harvest was in strip intercropping with 4 rows sweet basil (3.2) and secondary harvest was in sole crop sweet basil (2.5).

In order to investigate the effects of nitrogen fertilizer on yield and yield component of potato, (Solanum tuberosum L.) and researching for direct and indirect effects of some important agronomic traits, an experiment was conducted based on randomized complete blocks design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad, Iran, during 2008. Chlorophyll meter was used to identify the required precise time of potato to nitrogen fertilizer application. Nitrogen topdress fertilizer was applied at two levels (of 100 and 150 kgN.ha-1) and during two nitrogen index of 90 and 95 percent. Results of analysis of variance showed that 95 percent nitrogen index versus 90 percent nitrogen index has a better efficiency in increment of potato crop yield, but in 95 percent index, nitrogen fertilizer levels of 100 and 150 kgN.ha-1 did not showed significant difference in tuber yield. Results of path analysis indicated the traits of leaf nitrogen and large tuber percentage had the most positive direct effect on tuber yield and the traits of tuber specific gravity and tiny tuber percentage had the most negative direct effect on tuber yield. Supplying of nitrogen despite decrement of tuber specific gravity, increased tuber yield by increment of large tuber percentage. Assessment of correlation coefficient indicated that there are high correlations between SPAD reading, leaf nitrogen percentage and large tuber percentage and also there are high correlations between these traits and yield of potato. In general, it appeared that nitrogen fertilizer application by using chlorophyll meter, in addition to producing desirable yield of tuber, leads to make desirable quality of tuber and economy in nitrogen fertilizers application.

An experiment with a 33 factorial arrangement in a completely randomized design with 450 day-old broilers was conducted to study the effect of energy level and time of change from starter to finisher diets on performance and economic aspects of broilers. Broiler chickens were fed at three levels of dietary energy (2800, 3000, and 3200 KcalME/Kg) from 1-42 days of age. Starter and finisher diets were changed at 16, 21, and 26 days of age and then finisher diets were fed up to 42 days of age. The effect of diet energy and changing time from starter to finisher diets on body weight and feed conversion at 26 days of age were significant (P<0.01). By increasing energy level and changing time from starter to finisher diets, at this age, body weight increased and feed conversion ratio decreased. Energy conversion decreased by decreasing the levels of energy content of diet and increasing time of change from starter to finisher diets (P<0.01). At 42 days of age, the effects of diet energy and changing time from starter to finisher diets did not show any significant effects on feed and energy conversion in contrast, body weight at this age increased significantly as a result of increasing time of change from starter to finisher diets (P<0.05). From 1-42 days of age, the interaction between diet energy and changing time from starter to finisher diets on feed and energy conversion was significant (P<0.05). The results from this study suggest that increasing diet energy and changing time from starter to finisher diets for producing broilers with less than 2 kg will improve their general performance.